Yesterday's game in the world chess championship had some portentous overtones, but it finally settled down to an intricate, precisely balanced draw in 36 moves.

Some observers at the match site in Seville, Spain, had conjectured that challenger Anatoly Karpov might take a postponement because it was Game 13 played on Friday the 13th, and champion Gary Kasparov considers 13 his lucky number. But play went on as scheduled, beginning the second half of the 24-game match, and Karpov managed to neutralize the champion's massed 13s -- though not to crack his Gru nfeld Defense.

After losing to a Gru nfeld in Game 11, Karpov obviously had to try a new approach, but his switch was fairly minimal -- from one exchange variation to another. The Modern Exchange Variation, which branches from the standard in white's Moves 4 to 9, has been very successful for white. But six years ago Victor Korchnoi came up with the equalizing variation, starting with 10. ... Qa5ch, that was used by Kasparov yesterday. Karpov could have gambled with a pawn sacrifice, 11. Bd2, but in a match situation this kind of gallantry is hardly advisable.

So the game followed a familiar pattern. The white pawn on d5 was taboo. Had Kasparov played 16. ... Bxd5, then 17. Bb4, Rd8, 18. Bc4, he would have been forced to drop material. As is characteristic in this variation, white's passed d-pawn dictated strategic motifs for both sides; white tries to push the pawn through to d8, and black naturally tries to block it. This game did not give any clear indication which strategy has better prospects.

Kasparov seemed surprised by Karpov's 18. Be7, though it has been played before. He spent a long time in thought before answering it with 18. ... Bf6, a novelty. After 19 moves, Kasparov had used 54 minutes more than Karpov on his clock, but his game did not suffer unduly.

Kasparov's bishop turned out to be vital for the defense in controlling movements of the white knight. Karpov's bishop seemed paralyzed inside Kasparov's position, but that bishop was keeping Kasparov's knight tied into a defensive position. After 29 moves, the game was in equilibrium, neither side could make progress and a draw was the logical outcome.

Kasparov now leads in the match by a score of 7 to 6 with three wins, versus two for Karpov, and eight draws. The winner of the match will be the first player to score 12 1/2 points or win six games. Kasparov, who remains champion if the match ends in a tie, will have white in Game 14, scheduled to start on Monday.

Grandmaster Lubomir Kavalek contributed to this report.